RePower 1986 Marine Trader

IF please note the question is IF you had open choices and no pressure on you to act in a hurry.

What would you replace 250 hp TMAD 60C Volvo Pentas with ?

The Volvos are big heavy and not a joy to replace parts on for maintenance and repairs. way too much power for the hull and fuel burn for me to fund going fast.

I have taught classes on Yanmars and also like Perkins.

Any good positive advisement is appreciated

I'd be checking Isuzu and Mitsubishi. Finding out who marineizes them. Also I'd be thinking what gears to use. If you have those Volvos attached to BW gears your prop shaft is in line w your crankshaft. Using most any other gear the engines will need to be 2 or 3" higher.

Two smaller and lighter engines will increase efficiency through a lighter hull and possibly more efficient engines.

This will cost big bucks and the value of the resulting boat should be considered. Selling your Volvo powered boat and buying one w Cummins, JD or other desireable engines would probably be most cost effective. But the chance to choose your power loading is a fairly unique position to be in. Most boats being overpowered.

The prospect of going fast w/o burning more fuel is dim at best.

You mention Yanmar .. I saw on YW a 36GB that had been repowered w 55hp Yanmars. Using two turbo engines would be even smaller and lighter yet. And if they were small enough they could be run on boost that would be more efficient .. I think.

I'll 2nd the Isuzu, I've not been around any marinized versions but the ones in excavation equipment are problem free.


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Twin Disc MG506 had in-line input/output until you got into the deep case for
the deeper reductions. I had both.

Ted

I'd look for 80 HP John Deeres as perhaps the largest engines and go down only in size from there.

CPseudonym said:

I'd look for 80 HP John Deeres as perhaps the largest engines and go down only in size from there.

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what he said.

International DT 360 . , a running takeout, with under 5000-15,000 miles should cost well under $5,000.

Expected operating life , almost as good as a heavier Detroit.

SAE bell housing to fit a rebuilt Twin Disc.

Your choice of electronic injection or for cruising , simple mechanical.

These are very strong engines and should cruise at 1,500 for quietest on board experience.

Choice of tranny reduction to get best cruise.

Wet manifolds are available , but lagging the exhaust and a wet exhaust elbow is as quiet and far less expensive.

Buy a keel cooler and never bother with impeller replacement , or plugged intake , ever!

Autoteacher said:

IF please note the question is IF you had open choices and no pressure on you to act in a hurry.

What would you replace 250 hp TMAD 60C Volvo Pentas with ?

The Volvos are big heavy and not a joy to replace parts on for maintenance and repairs. way too much power for the hull and fuel burn for me to fund going fast.

I have taught classes on Yanmars and also like Perkins.

Any good positive advisement is appreciated

Click to expand...

What is the size and weight of the vessel?

Have you considered the Cummins 6BT? You can get factory re-manufactured ones that are basically new engines with mechanical fuel injection. They have a high displacement per HP and parts are cheap (they threw millions of these in trucks over the years).

I'd look no further than your local Cummins shop.

You can buy drop in ready factory remanufactured engines at a very good value.

The 6B 5.9L Cummins engine is a proven workhorse. Just think of all the Dodge Ram pickups that have used that engine for over a decade.

I am not a believer in the high RPM engines being produced today in terms of longevity. I do not have any hard data, except what I have seen as part of the backup power industry. Any day of the week a engine spinning at 1800 RPM will outlast an engine spinning at 3600 rpm. Before anybody squaks, I know we're not talking about generator engines as part of the OP's question but the same theory applies.

So, if I had a choice of a high speed light weight diesel, or a lower speed heavier diesel I'd choose the lower RPM unit hands down.

I'MREADYTOGO w READYTOGO,

Need to know how big and heavy this Marine Trader is.
Craig's leaning toward the Cummins is a bullit proff recomendation but the boat/owner may not need/want that much power. And how much power we're looking for has huge impact on what engines would/should be on the table.

The OP should give us some insight into what the performance of the boat is now and what he'd like to have going fwd.